The two questions that constitute the title of the paper are examined in the context of thought sequences, i.e., progressions of phrase-like expressions that spontaneously run through people 's minds. The analysis of a corpus of such sequences suggests that the articulation of thought in language affords fluidity that makes novelty possible. The articulation makes control possible, it lends momentum to thought, it presents alternative avenues for the further progression of thought, it renders thought into an activity akin to action in the real world, and it results in objectivization that provides compartmentalization and reflection. While the discussion focuses on the medium of language, it is noted that similar patterns hold with other media of articulation, both in natural cognition and in the arts. General implications are proposed and discussed.